What’s the Difference Between a Boiler and a Water Heater? Learn Pros, Cons, Cost, and More

Mizuki Hisaka
Written by Mizuki Hisaka
Reviewed by Joseph Wood
Updated June 16, 2022
A mother and her son doing the dishes in the kitchen sink
Photo: staticnak1983 / E+ / Getty Images


  • Boilers, also called furnaces, provide central heat and often hot water to your home.

  • Water heaters only provide hot water to your fixtures.

  • Boilers are more costly to install and repair.

  • There are more options for water heaters.

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It’s easy to take hot water for granted, but let’s face it—we need it. There’s only so long you can go without a hot shower, after all. Plus, the dishwasher depends on it, and a bubble bath just isn’t the same without warm water. 

Both boilers and water heaters supply your home with all the hot water you need, but they’re also very different. If you need to choose between the two, consider these points to decide on what would work best for you.

Boiler Pros & Cons

Boilers provide central heating for your home and hot water to your faucets (talk about two birds with one stone!). Although they can be a bigger investment upfront, they can save you money in the long run. Also remember that a boiler is different from a furnace, despite the term being used interchangeably.


  • Heat is evenly distributed

  • Less noisy than water heaters

  • No vents or forced air that blows allergens and dust

  • Typically lasts longer than water heaters

  • Costs less to run than forced-air systems


  • Costs two to three times more than water heaters

  • Replacement parts are more costly

  • Takes time for temperature to change after adjusting thermostat

  • Requires additional ductwork for central cooling system

Water Heater Pros & Cons

A professional testing a water heater
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Water heaters have one mission: to provide your house with hot water. It’s definitely one of the first must-have appliances you’ll want to install in a new home.


  • Less energy to run than boilers

  • Smaller in size (tankless)

  • Easier to install

  • Many different options

  • Lower upfront costs

  • Less expensive to replace


  • Requires separate system for central heating

  • Higher utility bills

  • Tankless may require water softener

  • Water temperature can be inconsistent

Boiler vs. Water Heater

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Boilers and water heaters are significantly different, but how can you choose? If you already have a central heating system, then you’re probably better off installing a water heater. However, if you’re building your house from the ground up, you might benefit from choosing a boiler system.


Standard boilers are designed for heating, but can also run a heating loop through a tank to heat your domestic water efficiently. Combination boilers will perform heating and domestic hot water without the use of a storage tank. 

“The standard boiler and ‘indirect’ tank are considered to be the highest quality, whereas the ‘combi’ boilers are much smaller have a shorter lifespan,” says Joseph Wood, Expert Review Board member and Master Plumber.

The main two types of water heaters are tank or tankless. The tank heaters heat the water and hold it in the tank until it’s needed. On the other hand, tankless heaters heat water on demand. They can also use a heat pump or a hybrid heater, which uses 60% less electricity because it uses heat in the air and the ground instead of electricity.

Most choices: Water heaters


Boilers can last 25 years or more, while combination boilers last about 10 to 15 years. Eventually, you’ll notice problems like odd noises, radiators taking a long time to heat, water leaks, or higher gas bills. High-quality boilers that are properly maintained have the best chances of lasting a long time.

Water heaters usually last around six to 10 years, with most carrying a six-year warranty.. Notably, if you consider the pros and cons of tankless water heaters, you’ll find that tankless models can last 20 years with a 15-year warranty. Common signs of a failing heater include water leaks, hissing sounds, and inconsistent performance.

Longest lifespan: Boilers, if you invest in a high-quality model


​Installing a new boiler costs $5,800 on average. A standard-efficiency boiler costs $3,000 to $6,000 and a high-efficiency boiler costs $6,000 to $11,000. Installation costs $1,000 to $2,500 on average, but some installs can reach $5,000.

Replacing a standard gas boiler costs $4,000, and replacing a high-efficiency boiler costs $7,500. These costs include a tank inspection, soil test, tank replacement, old tank disposal,  and environmental cleanup.

Additionally, if your boiler is powered by oil, you’ll need to account for periodic oil refilling. 50 gallons of oil could last all winter if your home is less than 1,000 square feet, with 100 gallons costing around $300 to $600. Note that this estimate will fluctuate as global oil prices change.

On the other hand, water heaters cost substantially less. A new water heater costs $1,200 on average with installation. Tankless heaters cost $1,000 to $3,000 while high-efficiency heaters cost $700 to $3,000, and installation ranges from $150 to $1,500.

Most affordable: Water heaters, if you already have a central heat system


Installing a boiler in your home requires extensive work, especially if you’re putting in a brand new system. Boilers are very heavy and have many complex parts. You would need to install the boiler, radiator, and the input and output pipes under flooring. For a job like this, it’s probably best to call a boiler installation company near you.

If you have some plumbing knowledge, you may be able to DIY a water heater installation. However, there are many steps involved and you’ll need some muscle to get it done.

Easiest to install: Water heaters


A plumber inspecting a boiler
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Generally speaking, if you’re noticing issues with your boiler, like leaks, temperature differences, or emissions problems, you’ll want to call an HVAC professional. Boiler parts are intricate and complex, so repairing them is not a typical DIY project.

If you call in a pro, you can expect the cost of a boiler repair to fall somewhere between $240 and $2,500.

Water heaters are easier for DIY repairs, depending on the problem. Most DIYers will be able to troubleshoot common issues like temperature being too hot or cold, the pilot light going out, or the heater working less efficiently.

If you have to hire a pro, the cost of a water heater repair ranges from $100 to $1,300.

Easiest to DIY repairs: Water heaters


Boiler maintenance requires an annual inspection of your boiler, vents, and wiring. Every six months, you should lubricate the circulating pumps and flush the boiler. Additionally, conduct a safety valve check monthly.

To maintain your water heater, you should conduct a visual inspection for leaks, test the water valve, and drain the tank to remove sediments.

Easiest to maintain: Water heaters


Boilers can be considered more sustainable because they harness the natural properties of hot water or steam.

But if you’re looking for something that is 100% sustainable, your only option is a solar water heater. These cost around $1,000 to $6,000 for the tank and $2,000 to $4,000 for installation. Although the upfront costs are high, it’s hard to beat having unlimited hot water without paying for electricity or natural gas.

Additionally, you can opt for high-efficiency tankless water heaters that use less energy.

Most sustainable: Boilers

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